In injection-molding machines, injection-speed control is generally performed in a manner such that a screw is driven for injection at an optimum injection speed for each of three or four sections, into which the injection stroke of the screw is divided. According to known injection-molding machines, an injection device is driven by means of hydraulic oil pressure. Meanwhile, a system has been developed such that the injection device is driven by means of a servomotor. In the servomotor drive system, however, the screw sometimes cannot force out a rigid resin whose viscosity in a fused state is low. The screw often fails to force out the rigid resin particularly if the acceleration/deceleration time (time constant) for its injecting operation, or the time before the screw reaches a set position, is shortened, that is, if the responsiveness is improved, in order to inject the resin in a short period of time. In such a case, the error between the values of an actual injection speed and an injection-speed command issued to the servomotor increases, so that an alarm may possibly be given. In this situation, it is troublesome, for example, to examine the cause of the alarm. In some cases, injection control should be performed so that the command speed is reached gradually by increasing acceleration/deceleration time, depending on the mold shape.